Conventionally, in a rotation drive device for obtaining a rotating force without using an engine or a motor, there have been a structure which is disclosed in patent document 1.
A rotation drive device described in the patent document 1 has a rotating shaft which is pivotally supported to a stand, a rotating table which is fixed onto the rotating shaft, and a plurality of rotating units which is provided at a plurality of positions which are spaced along a rotating direction on the rotating table. Each of the rotating units is provided with a weight which is provided on the rotating table so as to be linearly reciprocated in a direction which is orthogonal to the rotating shaft, and a fluid cylinder which linearly reciprocates the weight in the direction which is orthogonal to the rotating shaft. It is structured such as to change a position of the weight of each of the rotating units in a radial direction with respect to the rotating shaft, by sequentially supplying a fluid from a fluid supply source to a fluid cylinder of each of the rotating units by a rotary type switch valve which is provided on the rotating shaft, and rotate the rotating table and the rotating shaft on the basis of a fluctuation of a rotating moment which a gravitational force applied to the weight acts around the rotating shaft.